The worst one I came across was when I was buying a HP laptop to repair and sell. Everything was supposed to be ok with it apart from the keyboard was missing and so was the DVD and hard drive that's all fine and replaceable I thought. So I ordered all the new parts and a new quad core for it and once they arrived I started to strip down the laptop and as soon as I took the top case I could see it blue/black coloured MOULD!!! It was everywhere and had started corroding the motherboard that greenish colour copper goes when it corrodes. It was properly nasty I had to scrub the motherboard and case with a toothbrush and water to try and get everything. My best guess is that a can of beer got emptied inside it and they didn't know how to take it apart so took the hdd,DVD and keyboard off to hide the damage. I wish I had a photo.

You have to physically put that link in to your comments every time, so either you're a spammer (I sure hope not), or you're new and dont know where the signature edit function is. I'll assume you're just new, so here's the link to edit your signature, so you can put that link of yours in the right place, and look less suspicious.

Here's an old pic of my MSI Twin Frozr R7950 w/ Thermaltake Water 2.0 Performer. Was used for Bitcoin mining for several months with light cleaning in between. The photo below is when I hadn't cleaned it for about 2 weeks.

oh well its not from me but from a random WTF computer post on facebook

hum ...
at last the owner has the reason why his fan stoped working ... and judging by the lizard look ... it has been a long time before he'd notice it ...

i posted it somewhere else but thanks to Random Murderer now i know that topic
i had many computer and many dust problem but now i dont have any i learned the lesson and unluckly i didnt take any pics of them ... but i might have some pic of gpu i brought for cheap and surprise i got when i dismantled them to clean and refresh TIM...time for diging thru imageshack pics and BRB.

1st a generic Nvidia 9800GT 1gb from HP
and the one who sold me this stated "not working anymore overheat like mad, dunno why"

2nd ASUS Radeon 4870 512mb same excuse for "non working state"

As i said in nostalgic hardware club ... DONT CLOSE YOUR COMPUTER CASE IF YOUR CAT IS MISSING!!!

also ... buisness class dont mean no cleaning needed but its far better than some comp i've seen here...